ML20211F707
| ML20211F707 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 08/03/1986 |
| From: | Mangan C NIAGARA MOHAWK POWER CORP. |
| To: | Starostecki R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| (55(E)-86-14), (NMP2L-0806), (NMP2L-806), NUDOCS 8610310232 | |
| Download: ML20211F707 (2) | |
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M Y NIAGARA RUMOHAWK NBAGARA MOHAWK POWER CORPORATION /300 ERIE BOULEVARD WEST. SYRACUSE, N.Y.13202/ TELEPHONE (315) 474-1511 August 3, 1986 (NMP2L 0806)
Mr. R. W. Starostecki, Director U.S. Nuclear Regulatory Commission Region I Division of Reactor Projects 631 Park Avenue King of Prussia, PA 19406 Re:
Nine Mile Point - Unit 2 Docket No. 50-410
Dear Mr. Starostecki:
Enclosed is a final report, in accordance with 10CFR50.55(e), for the problem concerning control cable length verification.
This problem was reported via 4
tel-con to G. Meyer of your staff on July 3,1986.
Very truly yours, C. V. Manga Senior Vice President CVM/GG/cla (1717H) xc:
Director of Inspection and Enforcement U.S. Nuclear Regulatory Commission Washington, DC 20555 W. A. Cook, NRC Senior Resident Inspector NMPC Project File a
8610310232 860803 PDR ADOCK 00000410 l
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NIAGARA M0 HAWK POWER CORPORATION NINE MILE POINT - UNIT 2 DOCKET N0. 50-410 Final Report for a Problem Concerning Control Cable Length Verification
( 55(e )-86-14 )
Description of the Problen When considering minimum design vol tage being present at the 120-V ac and 125-V dc distribution system, the minimum voltage required of certain Class lE equipment to operate was not met.
This problem was identified during an effort designed to verify whether the minimum voltage requirement of devices located in or wired through the control roon was satisfied.
The cause of this problem is attributed to the following reasons:
1.
Long cable lengths 2.
Wiring equipment such that the ampacity varies at different parts of the circuit.
Analysis of Safety Implications Had this condition remained uncorrected, it woul d have a ffected the short and/or long tern perfornance of the Class lE equipment, and therefore could have adversely affected the safety of operations of the plant.
Corrective Action Design changes have been issued to correct circuits where unacceptable conditions occurred.
The initial objective of these changes is to reduce the circuit resistance of the cables so that the voltage drop is reduced to an acceptable l evel.
The design changes are on Engineering and Design Coordination Reports Y07801, Y07801B, and Y07801E.
If cable nodi fica tions do not resul t in acceptable vol tage drops, then interposing relays with lower operating vol tage requirement are used in conjunction with the existing contactors/ relays.
These changes are identified on Engineering and Design Coordination Reports YO7804 and YO7801C.
The above corrective actions will be conpleted by fuel load.
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